Tex. Transportation Code § 203.052

(a) The commission may acquire an interest in real property, a property right, or a material under Section 203.051 only if the commission determines that the acquisition is necessary or convenient to a state highway to be constructed, reconstructed, maintained, widened, straightened, or extended.

(b) Property necessary or convenient to a state highway for purposes of Subsection (a) includes an interest in real property, a property right, or a material that the commission determines is necessary or convenient to:

(1) protect a state highway;

(2) drain a state highway;

(3) divert a stream, river, or other watercourse from the right-of-way of a state highway;

(4) store materials or equipment for use or used in the construction or maintenance of a state highway;

(5) construct or operate a warehouse or other facility used in connection with the construction, maintenance, or operation of a state highway;

(6) lay out, construct, or maintain a roadside park;

(7) lay out, construct, or maintain a parking lot that will contribute to maximum use of a state highway with the least possible congestion;

(8) mitigate an adverse environmental effect that directly results from construction or maintenance of a state highway;

(9) subject to Subsection (c), provide a location for an ancillary facility that is anticipated to generate revenue for use in the design, development, financing, construction, maintenance, or operation of a toll project, including a gas station, garage, store, hotel, restaurant, or other commercial facility;

(10) construct or operate a toll booth, toll plaza, service center, or other facility used in connection with the construction, maintenance, or operation of a toll project; or

(11) accomplish any other purpose related to the location, construction, improvement, maintenance, beautification, preservation, or operation of a state highway.

(c) The commission may not acquire property for an ancillary facility through the exercise of eminent domain, unless the acquisition of the property is for one of multiple ancillary facilities included in a comprehensive development plan approved by the county commissioners court of each county in which the property is located.